Magazine strip for ratchets and tool for handling the same

ABSTRACT

A magazine strip of tie ratchets ( 1 ) which are provided for holding the ends of ties for binding elongated articles such as cable harnesses and are connected to one another by webs ( 10 ), the width of which is not greater than half the ratchet width and which are arranged adjacent to the tie entry side ( 7 ) of the ratchets ( 1 ) The webs have a length of not more than 1.3 mm and/or one sixth of the ratchet dimension in the direction of the magazine strip. The width of the essentially parallel wall sections which carry the webs is expediently not greater than three quarters of the entire width of the ratchets. The thickness/width ratio of the webs should be not greater than ⅕. The invention also relates to a tool for binding cable harnesses which ensures that the webs are cut exactly in the center.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 10/467,472,filed Aug. 8, 2003.

BACKGROUND OF THE INVENTION

For the mechanical binding of articles, in particular cable harnesses,by means of tie loops, the ends of which are held by tie ratchets, thetie ratchets are fed to the binding tool in the form of a magazine stripin which the tie ratchets are connected to one another by flexible webswhich in each case are cut in the tool before use. If the webs aresevered only by one cut, projecting stubs remain behind. It is certainlyalso known to avoid these stubs by the webs being removed essentiallycompletely by two cuts executed at their ends. How-ever, this results inscrap, which in many applications (for example in aircraft or satelliteconstruction) must not be left in-situ in an uncontrolled manner and istherefore undesirable. The invention therefore assumes that a stub pieceremains on the ratchet when the web is severed. This stub piece may besharp-edged and may lead to a risk of injury, in particular if theseparating cut is not executed in the center (EP-B-297 337, FIG. 3) orif it is arranged on a laterally projecting flange (U.S. Pat. No.4,610,067, FIG. 1). But even when the web is cut symmetrically andprojects directly from those walls of the ratchets which are parallel toone another, it is relatively long in relation to the dimensions of theratchet (U.S. Pat. No. 4,680,834, FIGS. 6 to 8).

SUMMARY OF THE INVENTION

An object of the invention is therefore to reduce the problem of therisk of injury on account of the web stub projecting from tie ratchets.The solution according to the invention consists in the provision of amagazine strip of tie ratchets which are provided for holding the endsof ties and binding elongated articles such as cable harnesses and areconnected to one another by webs. These webs have a length of not morethan 1 mm and/or one eighth of the ratchet dimension in the direction ofthe magazine strip. By the correlation between the known feature thatthe width of the web is not greater than half the width of the ratchetand the novel feature that its length is not greater than 1 mm (thelength of the web stub is therefore not greater than about 0.5 mm), therisk of injury is considerably reduced.

Since the length of the web between adjacent ratchets is small, thedistance between those surfaces of these ratchets which face one anotheris also small. This may cause problems at the injection molds in whichthese ratchets are produced. These molds contain a group of moldcavities for one ratchet in each case. The distance between the ratchetsis formed by mold walls which separate the mold cavities. For reasons ofstability and heat dissipation, these walls cannot be made as thin asdesired. This is one of the reasons why in previously known magazinestrips the distance between adjacent ratchets and therefore the weblength are greater than is desirable according to the present invention.

The invention has recognized that the distance between the ratchetsurfaces and therefore the web length can be reduced by the width ofthose surface sections of the adjacent ratchets which are approximatelyparallel to one another being made substantially smaller than the widthof the ratchets. This is achieved by those sides of the ratchets whichface one another being substantially parallel to one another only in acenter, limited region, whereas to the side of said region they aredefined by inclined surfaces which diverge and form a space widening ina wedge shape. For the production molds, this means that the mold wallsbetween adjacent mold cavities are firstly formed by a pair ofwedge-shaped, thick and stable structures which hold a narrow wall piecebetween them, which may be relatively thin on account of its smallwidth. The width of the essentially parallel surface sections isexpediently not greater than three quarters, or else preferably notgreater than two thirds, of the entire width of the ratchets.

It is certainly conceivable for the webs to be arranged not directly onthe walls forming the ratchet body but on a bead which projects fromeach ratchet in the direction of the adjacent ratchet and which isthickened relative to the web. Even then, however, the distance betweenthose essentially parallel surface sections of the ratchets which faceone an-other, in their region which carries the web or the bead, isexpediently not greater than 1 mm. The bead may be formed by the rootregions of the webs being thickened in relation to the center region ofthe webs. Regarded as the root region of a web is that region of the webwhich is adjacent to the wall surface carrying the web.

The webs are arranged adjacent to the tie entry side of the ratchets.The tie entry side refers to that side of a ratchet from which the endsof the tie loop enclosing the article to be bound enter the ratchet.This side is predetermined by the arrangement of the locking members inthe ratchet.

In known magazine strips (U.S. Pat. No. 4,610,067, U.S. Pat. No.4,680,834), the web is designed to be extremely narrow. The reason forthis is obviously due to the fact that the web cross section is to bekept small in order to reduce the cutting force which has to be appliedin order to sever it. However, the narrowness of the web has thedisadvantage that the magazine strip is unstable. There is in particularthe risk of the ratchets being twisted relative to one another about thelongitudinal direction of the strip. This may result in problems whenguiding the magazine strip into a handling tool. The invention achievesgreater stability of the magazine strip owing to the fact that the widthof the webs is equal to at least one quarter of the ratchet width.Nonetheless, it succeeds in keeping the cutting forces small, namely bythe ratio of thickness to width of the webs being kept small, namely notgreater than ⅕. This ratio, in combination with the large web width,results in an extremely small thickness. The web therefore assumes theform of a thin film which can be easily cut but offers a high resistanceto lateral bending (about an axis extended transversely to the webplane) and torsion of the magazine strip.

The connecting web is expediently connected to the adjacent ratchets inone piece by common hot plastic forming. If this is not possible, theweb should be connected in one piece to one of the two ratchets and in apositive-locking manner to the other one, the positive lockingexpediently being achieved by the web having end thickening which isenclosed by the material of a ratchet from the hot plastic state.

The desired shortness of the web stubs, at a minimum length of the webswhich is predetermined in practice, depends on whether the webs are cutin the center. This requires accurate positioning of the web to be cutin the handling tool. Positioning of the ratchets in the handling tooltakes place in the case of known tools only at the ratchet holder, whichreceives the foremost ratchet of the ratchet chain for handling.Therefore, in known tools for handling ratchet chains, provision is madefor the cut to be carried out close to the ratchet holder. However, thisis disadvantageous, because many components are crowded there anyway.The intention of the invention is therefore to provide the device forseparating the ratchets at a greater distance from the ratchet holder.However, on account of the distance tolerances of the ratchets, noaccurate positioning of the ratchets can be expected there if only thatratchet which is located in the ratchet holder is accurately positioned,and no cut exactly in the center of a web dimensioned to be very shortcan be expected. The invention solves this problem by the separatingdevice being arranged on a support part which is movable in the feeddirection of the ratchets and which also carries a positioning devicefor the magazine strip. This positioning device may be formed by thedriver, which is to be provided anyway for the feed of the magazinechain.

When the width of a component is referred to in the present connection,this always means the dimension transversely to the longitudinaldirection of the magazine strip and transversely to the direction of thetie passage opening provided in the ratchet. The term “length” refers toa dimension in the longitudinal direction of the magazine strip. Theterm “thickness” refers to the dimension perpendicular to the surfaceextent of the relevant part.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained below in more detail with reference to thedrawing, which illustrates an advantageous exemplary embodiment and inwhich:

FIG. 1 shows a longitudinal section through three ratchets of a magazinetie;

FIG. 2 shows a plan view corresponding to FIG. 1 in arrow direction“II”;

FIG. 3 shows the partly sectioned view of a ratchet in the bound state;

FIG. 4 shows a plan view of the arrangement according to FIG. 3 in arrowdirection “IV”;

FIGS. 5 to 7 show three schematic sections through a tool in variousfunctional states;

FIG. 8 shows a view of the locking pawl arrangement; and

FIG. 9 shows a greatly enlarged longitudinal section through a web andthe adjoining ratchet parts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Each of the ratchets, which are shown greatly enlarged in therepresentation, comprises an encircling wall which is composed of wallsections 1 parallel to the direction of the magazine strip, wallsections 2 running perpendicularly to this direction, and obliquelyrunning transition sections 3. It contains a through-opening 4 for theties to be bound and locking pawls 5, which interact with a tooth systemof these ties. The locking pawls 5 are arranged in such a way that—theyallow the toothed ties to enter the ratchet in arrow direction “6”, butlock in the opposite direction. The side 7 of the ratchets is thereforereferred to as tie entry side.

Adjacent ties of the magazine strip are connected to one another by webs10. The latter are mostly made in one piece with both adjacent ratchets.However, depending on the type of production, they may also be connectedin a positive-locking manner to at least one of the two ratchets. Thisis shown at the web 10 a, the thickened, undercut head 11 of which isenclosed by the wall material 12 of the associated ratchet. Theenclosure is achieved by the end of the web 10 a having been insertedinto the mold of the ratchet before the hot plastic forming of thelatter and by the material, 12 therefore having flowed around this endbefore it had solidified.

The distance A between the surfaces 2′ of the wall sections 2 in theirregion close to the web 10 is expediently 0.8 to 1.3 mm, or elseexpediently up to 1.1 mm. It should not exceed one sixth, preferably oneeighth, of the length of the ratchet. The root regions 13 of the webs 10are designed such as to be thickened bead-like relative to the centerregion 14. This firstly improves the force transmission between the wallsections 2 and the webs 10 and also reduces the remaining length of thethin web stub after the cut, which stub may cause injury. The length ofthe thin web part between the beads 13 is expediently not greater than0.6 mm. The length of the web stub remaining (including bead) is not tobe greater than 0.7 mm and/or not greater than one tenth (preferably onetwelfth) of the ratchet length. In the example shown, the webs 10(including bead) have a length which corresponds to about one eighth ofthe length of the ratchets.

The thickness D of the web depends on the flexibility and strengthrequired and is, for example, 0.2 to 0.4 mm or less than one tenth,preferably less than one fifteenth, of the ratchet height.

The width of the web is not greater than about half the width of theratchets and is not greater than the width of the tie. The side edges 8of the webs 10 are therefore set back from the ratchet edge line 15 by adistance 16 which should be in the order of magnitude of 2 mm and shouldbe at least one eighth, preferably at least one fifth, of the ratchetwidth. However, the web width is at least about one fourth to one thirdof the ratchet width. The ratio of thickness to width of the webs is asa rule ⅕ to 1/10 and possibly more.

During the handling of the ratchets, they are singularized by a cutapproximately in the center of the web. Web stubs 17 are left behind,the position of which in relation to the ratchet, to the tie loop 18 andto the bound article 19 is illustrated in FIGS. 3 and 4. It can be seenin FIG. 3 that the web stub 17 lies at the depth of the spatial gussetwhich is formed by the adjacent wall section 2 of the ratchet and thetie loop 18 or the article 19. In view of the small length of the webstub and its protected position, it is extremely unlikely that a personwill brush against this point inadvertently in such a way that thisperson could be injured.

The small distance between the ratchets in the magazine strip, thisdistance permitting the small length of the webs, requires a small wallthickness of the mold, used for the production, between those wallsections 2 of adjacent ratchets which are opposite one another. If thissmall wall thick-ness had to be provided over the entire width of theratchets, this could be problematic. However, it is quite safe if,according to the invention, the width of the wall sections 2 and thusthe width of the mold wall referred to are substantially smaller thanthe entire width of the ratchets. Between the obliquely running wallsections 3 of adjacent ratchets, the mold wall may be amply dimensionedand therefore offers good stability and heat dissipation.

The width region of the surfaces 2′ of the wall sections 2 in which thelatter run approximately parallel to one another should be not greaterthan three quarters and furthermore preferably two thirds of the entirewidth of the ratchets. It goes without saying that the ratchet wallsneed not be of strictly polygonal construction for forming the wallsections 2 and 3, although this is expedient. The approximately parallelcourse of the surfaces 2′ of the wall sections 2 carrying the webs andthe course of the outer wall sections 3 which is inclined thereto mayalso be reproduced by a continuous curve, as indicated by dot-dash linein FIG. 2 at the lower-most ratchet. Inclinations of less than 150,possibly even greater inclinations, are to be regarded as essentiallyparallel. The height 20 of all the edges of the web stub 17 above theadjacent edge 21 of the tie entry side, over which the tie 18 runs inthe bound state, should be not greater than 2 mm (measured parallel tothe wall section 2), preferably not greater than 1.2 mm. In the exampleshown, this dimension is about 1 mm. Expressed in fractions of theratchet height 22, this dimension should not exceed one quarter,preferably one fifth.

The handling tool is explained below with reference to FIGS. 1 to 8. Onits front end, the tool body 31 with a handle 32 has a holder 33 (notshown in any more detail) for a ratchet 34, and a tie 35 is passedthrough this holder 33 in the direction of the arrows, with means whichare unimportant in the present connection, is wrapped in the form of aloop 37 around an article 36 to be bound and is returned with its freeend into the ratchet 34. After that the tie is tensioned, the projectingstrand 35 is cut off, and the ratchet 34 is released from the ratchetholder 33 (FIG. 7).

In order to permit largely automatic operation, the ratchets to behandled are automatically fed to the ratchet holder 33; From astationary large magazine (not shown), they reach the tool body 31 inthe form of a ratchet chain 41, in which the individual ratchets 1 areconnected to one another by webs 10. At the tool body 31, the ratchetchain 41 is received by a guide channel 44, which opens out at theratchet holder 33.

A device 50 for feeding and singularizing the ratchets is provided atthe guide channel 44. The representation of the guide channel 44 isinterrupted in the region of this device 50. However, it goes withoutsaying that a guide for the ratchet chain 41 is also provided in thisregion. Parallel to this ratchet guide, a slide 51, which is illustratedby dots in the drawing, is mounted such as to be movable parallel to theratchet guide in arrow direction 52. Two guide walls 53 schematicallyindicate the slide guide. Provided for driving the slide is a lever arm54, which interacts with the slide 51 in a suitable manner at 55 and ispivotable about a pivot pin 56 fixed to the tool body 31. It is rigidlyconnected to a cam lever 57 which projects into the revolving path oftwo cams 58 which are arranged on a cam plate 59 which is rotationallydriven counterclockwise about the axis 60 by an electric motor.

Rigidly connected to the lever arms 54, 57 is a third lever arm 61 whoseend is linked to the push rod 62 of a compression spring 63. The spring63 pushes the lever arm 61 upward (in the representation) and therebypushes the end of the lever arm 54 in the direction of the front of thetool. On the other hand, if a cam 58 comes into engagement with the camlever 57, as shown in FIG. 7, the cam lever 57 is pushed downward.

At the same time, the lever arm 61 is also moved downward, as a resultof which the spring 63 is loaded. The lever arm 54 and with it the slide51 are moved to the right (in the drawing), that is to say against thefeed direction of the ratchet chain 41. If the cam 58 has passed the camlever 57, the spring 63 attempts to pivot the lever arrangement 54, 57,61 counterclockwise and thereby attempts to move the slide 51 in thefeed direction.

A locking pawl 70 is linked to the slide 51. It is designed and arrangedin such a way that its tip is pushed into engagement with the ratchetchain 41 by a spring (not shown). In more general terms, the pawl 70 hasa surface, which can come into engagement with a ratchet surface turnedtoward the rear in order to exert a feed force thereon.

Furthermore, a rocker 71, which is acted upon by a spring (not shown) inarrow direction 72, is linked to the slide 51. On its front end, itcarries a blade 73, which is intended to sever a web 10 betweensuccessive ratchets 1 during a Movement against the arrow direction 72.A cam lever 74, which seizes the rear end of the rocker 71 by means of anose 75, is provided in order to effect this cutting movement of therocker 71. Its bottom end projects into the revolving path of the rotarycams 58. If it is seized by a rotary cam according to FIG. 6, the pivotlever 74 is pivoted clockwise and the rocker 71 is pivoted against thearrow direction 72. The blade 73 performs the cut in the process. In theembodiment shown, the cam lever 44 is linked to the slide. Instead, itmay also be attached to the tool body provided its interaction with therocker is ensured.

The pawl 70 is designed in such a way that it always inter-acts with theratchets 1 in the same way. The ratchet seized in each case by the pawl70 is therefore located in a precisely defined position in relation tothe pawl. Since the pawl 70 and the blade 73 are arranged at a fixedmutual distance apart on the slide 51, and since the ratchets alwayshave the same form and are always at the same distance from one another,this ensures that the blade 73 always strikes the web 10 between twosuccessive ratchets 1 exactly in the center. This would not be ensuredif the cutting device were arranged in a fixed position on the toolbody. For the respective position of the slide in relation to the toolbody is undefined, as emerges from the subsequent description of themode of operation.

Since the representation in FIGS. 5 to 7 is highly schematic, the way inwhich the locking mechanism is expediently embodied in a practicalmanner is shown FIG. 8. The slide 51 is arranged on both sides of theratchet chain 41 and forms guides 65 for the latter. The cutting deviceis omitted from the representation. On each side of the ratchet chain41, it carries a respective locking pawl 70 a, which is pressed from theside by a spring (not shown) into the intermediate space, expediently ofwedge-shaped design, between two ratchets 1. As a result, clearlydefined positioning of the ratchets relative to the slide 51 isachieved. Arranged in a fixed position on the tool housing is a furtherpair of locking pawls 78 which are likewise pressed by spring forceagainst the ratchets and ensure that the ratchet chain is held in placeduring the return of the slide 51 (to the right in FIG. 8).

The binding of the article 36 by means of the loop 37 takes place in thestate in FIG. 5. In this state, the spring 63 exerts a feed force on theslide 51 via the lever arrangement 61, 541 and this feed force istransmitted to the ratchet chain 41 via the locking pawl 70. As aresult, the foremost ratchet 34 is pressed reliably into the ratchetholder 33, the position of the slide 51 being determined by the lengthof the ratchets located between the foremost ratchet 34 and the lockingpawl 70, on which ratchets the slide is supported under the spring force63. Since this ratchet row located in front of the slide 51 consists ofsingularized ratchets, the distance apart of which does not necessarilycorrespond to their distance apart before the singularizing, theposition of the slide 51 in this state is subjected to randomfluctuations within a certain tolerance range. This is the reason whythe cutting device 73 is arranged together with the pawl 70 on the slide51.

During the working cycle of the tool, the cam plate 59 rotatescontinuously in the direction of the arrow. When the binding operationhas been completed, a cam 58 reaches the bottom end of the cam lever 74and pivots the latter according to FIG. 6, as a result of which the lastratchet located in the slide is cut off from the remaining ratchet row.When the cam 58 has left the cam lever 74, the latter together with therocker 71 swings back again under the spring force 72 into the positionaccording to FIGS. 5 and 7.

The cam 58 now reaches the end of the cam lever 57 and thereby pivotsthe cam arrangement clockwise. As a result, the spring 63 is loaded andthe slide 51 is displaced to the rear (to the right in FIG. 7) byslightly more than a ratchet dimension. During this return stroke, thelocking pawls 78 (FIG. 8) hold the ratchet row in place. In the process,the pawl 70 (or the pawls 70 a) slide along a ratchet beyond its rearsurface, which is to be seized during the next feed motion. As soon asthe cam 58 has left the end of the cam lever 57, the slide 51 moves inthe feed direction under the effect of the spring 63. In the process,first of all the pawl 70 (or the pawls 70 a) engages in the nearestratchet gap. As soon as the connected article 36 together with theforemost ratchet 34 has been removed from the tool and the ratchetholder is therefore empty, the slide 51 is moved further together withthe ratchet chain until the ratchet which is now the foremost ratchethas reached the ratchet holder 33. The resistance which this ratchetfinds in the ratchet holder is transmitted via the further ratchet chainup to the locking pawl 70 and the slide 51 and holds the latter inplace. In the process, the force of the spring 63 or the feed force ofthe slide 51 constantly acts on the ratchet chain located in front ofthe slide. Since the ratchet in front of the pawl 70 is still connectedin one piece to the following chain of ratchets, the latter is alsotightened accordingly.

The invention has the advantage that the separating cut betweensuccessive ratchets can be effected at a very accurately definedlocation and therefore the length of the web 10 which connectssuccessive ratchets can be dimensioned to be very small. The stubsremaining on the ratchets are so short that they do not cause any riskof injury. They do not need to be removed. A cut free of scrap istherefore sufficient for this singularizing of the ratchets. Anadvantage of the invention also consists in the fact that thesingularizing of the ratchets may take place at any desiredconsider-able distance from the front of the tool, where it is difficultto accommodate a cutting device for the ratchets on ac-count of thespace available.

1. A tool for binding elongated articles with a tie having ends securedby a ratchet connected to other ratchets by a web to form a magazinestrip, said tool comprising: a ratchet guide configured to controlmovement of the ratchets within said tool, said ratchets having a feeddirection; and a device for feeding and separating the ratchets, saiddevice comprising: a support arranged to reciprocate in said feeddirection and back along a path parallel to said ratchet guide; a bladecarried by said support and arranged to sever the web to separate theratchets from the magazine strip; and a feed pawl carried by saidsupport and arranged to exert a feed force on said magazine strip duringsupport movement in said feed direction, wherein said pawl and saidblade are arranged at a fixed distance from each other in the feeddirection.
 2. The tool of claim 1, wherein an intermediate space isdefined between ratchets in said magazine strip and said devicecomprises a pair of positioning pawls carried by said support andarranged on opposite sides of said magazine strip, said positioningpawls biased toward a position in said intermediate space on either sideof said magazine strip, thereby positioning the magazine strip relativeto said support.
 3. The tool of claim 2, wherein said intermediate spaceis wedge-shaped and said positioning pawls have a complementary shape.4. The tool of claim 1, wherein said blade is mounted on a rocker armcarried by said support for pivotal movement, said rocker arm acted onby a lever to sever said web.
 5. The tool of claim 1, comprising asecond pair of positioning pawls fixed to a body of the tool and biasedtoward engagement with said magazine strip to hold the magazine strip inplace during support movement opposite said feed direction.
 6. The toolof claim 1, wherein said web is severed by said blade during advancementof said ratchets in the feed direction.